Fluorography



July 1o, 1951 Filed Feb. 6, 1947 L. M. E. cLAUslNG 2,560,085

FLUOROGRAPHY zlsheetssheet 1 un g llllllllllIlillk\\\ IN VEN TOR.

fm2/airy gmawm July l0, 1951 L. M. E. cLAuslNG 2,560,085

' FLUOROGRAPHY Filed Feb. 6, 1947 2 sheets-sheet 2 lnrlllllllhvlllzv nll mmmm/ Illinil INVENTOR.

Patented July 10, 1951 UNITED STATES "PATENT FFICE Y FLUonoGRAPHY LeroyE. Clausing, Chicago, Ill. Application February 6, 1947, Serial No.726,874

(Cl. Z50-65) 8 Claims.

This invention relates to the making of fluorograms and moreparticularly to iluorographic equipment therefor.

Fluorograms made according to present methods and with known equipmentare not entirely satisfactory because of the diiiiculty of securingsuiiicient density of the image on the film with the present type highspeed lens. It is an irnportant lobject of the invention to providemeans for overcoming these difliculties in making fluorograms. Y

Another object of this invention is to provide means for makingfiuorograms on roll film by means of a camera of the spherical mirrortype.

The normal lens-mirror optical system requires an image surface which isin the form of a portion of a sphere and it is, therefore,V

prevents the use of a continuous film strip and the taking of successivepictures on a roll of lm or a continuous film strip and the second isundesirable'because of the loss of light by reneetion on the surfaces ofthe field-flattening lens and because that lens being very close to thefocal surface unavoidable dust and other foreign matter on the lens willshow prominently on the fluorogram. It is, therefore, a furtherimportant object of the invention 4to provide means for takingfluorograms upon a continuous film strip or roll of iilm.

Other and further objects will be apparent from the followingdescription when taken in connection with the accompanying drawings.

wherein:

Fig. 1 is a plan view of an apparatus embody- Fig. 5 is a view inhorizontal section takenv substantially along the line 5-5 of Fig. 4;

Fig. 6 is a plan view similar to Fig. 1 showing another form ofapparatus embodying the invention; and

As shown in Figs. 1 to 6, the photographic equipment or camera formaking iluorograms comprises a fluorescent screen 2 upon which afluorescent image is formed of the object 4 by means of X-rays from theX-ray source or tube 6. The screen is positioned at the outer end of alight-tight box or housing 8 joined at its inner end to a housing I0. Atthe rear end of the housing lll there is mounted, in any convenientmannen a spherical mirror l2 axially aligned with an opening I4 in theforward end of the box I0 and with an aplanatic vor aspherical,correcting plate lens IB mounted in a lens holder I8 fastened to thevbox I0 in any convenient manner.

A film box 20 is detachably mounted in a frame 22 supported by diagonalarms 24 fixed at their outer ends to an apertured partition 26.

The film box 20 is detachably held in the frame 22 by means of opposedspring-plate latches 28. The film box 20 is open at its front end,facing the mirror I2, and is closed at its back end, facing the lens I6.In the back end of the box there is mounted an X-ray opaque plate 32,preferably of lead, for excluding the direct X-rays from the box. l

Within the box 20 is mounted, in a conventional manner, means detachablyto receive a film supply roll 34 and a take-up reel 36, which latter,

' 4'in the conventional manner, is rotated by means of a shaft 38 towhich it is detachably interlocked. The shaft 38 is provided, externallyof the box,'with a gear 40 meshing with a gear 42, in turn meshing witha gear 44 mounted on the l lower end of a vertical shaft 46 projectingstantially along the line 'I-l of Fig. 6.

supporting backing plate 52 and over a second guide roller 54 to thetake-up reel 36.

Heretofore in taking pictures with this type of camera, i. e., oneincluding a spherical mirror which focuses the received rays on the filmsurface, it has been thought necessary to provide a film supportingsurface of spherical form and of a definite radius relation to thespherical mirror. It has, therefore, been necessary to bend the film orplate to the shape of this spherical backing plate in order to getimages of suiiicient definiteness for practical purposes. This hasprevented the use of a camera in taking pictures upon a continuousstripr where portions of the strip are exposed successively.

I have discovered that this limitation of the use of the camera may beavoided in the making 3 ci' X-ray fluorograms by forming the fluorescentscreen a in the shape oi a portion or a cylindrical sui-race anc.forming the fiim backing plate 52 also in ne shape or a cylindricalsurface Whose center or revolution or axis is perpendicular to thecenter of revolution or axis of the cylindrical surface of thefluorescent screen 2. With the screen and nlm backing plate thus formedas cylinders Whose axes are perpendicular to each other and Withtlieobject positioned against the concave side or" the fluorescentiscreen 2, the image formed on the lm by reflection from the sphericalmirror i2 is sharp except at the veryA edge of the four corners of thefilm surface, which usually does not receive any portion of the imageanyway, so that the indeniteness at these corners is of no particularconcern. Since the objects of which a fluorogram is .desired rare some.

part or parts of the human body Which are convex in shape, theconcave-convex fluorescent screen provides a very conveniently shapedsurface for application to such parts. It should be-noted also that thisconcave-convex fluorescent screen provides a marked improvement indeniteness in the fluorescent image on the screen for it conforms moreproperly to the contour of the part 'to be luorographed, it makes thedistance between the object and screen more uniform, and it conformsmore nearly to the diverging rays from the X-ray target.

I have further discovered that in instances where the shape of theobject permits, the fluorescent screen 2 may be formed in theV shape ofa portion of a sphere With the radius of the fluorescent image surfaceof such valuel that With the particular lens-mirror system, the focalaxis of whichpasses through thecenter of the sphere, the lm imagewill-be formed upon a plane surface at the focus of the sphericalmirror, so that the film backing plate 52 may be a flat plate .or anyother shape of p-late having a plane surface, against which the film ismoved and on which it rests Whilerexposed. Inmany cases, such a screenwill conform closely to the shape of the object or part of the humanbody which is to be fluorographed and will present a surface of nearlyequal radius to the diverging X-ray beams.

rihis invention also eliminates the lead glass shield normally used toprotect the, film from exposure to X-rays and shields the film fromdirect exposure to X-rays by use of the plate 32 of metallic lead orother X-ray-opaque material positioned at the back surface of the film.More efficient protection against high intensity X-rays can thereforemore readily be secured.

It will, therefore, be evident that I have-provided means for makingiluorograms by means of a camera of the spherical mirror type whichovercomesV the difficulties formerly encountered in making fluorograms,and which makes it possible and practicable to take-fluorograms upon acontinuous nlm strip or roll of film.

It is obvious thatA numerous changes may be made in the form,construction and arrangement of the device Without departing from thespirit or scope of the invention or sacrificing any of Yits attendantadvantages, the form herein described being a preferred embodiment forthe purpose of illustrating the invention.

l claim:

l. Means for taking X-ray pictures comprising a fluorescent screen, amirror-correcting plate lens system, film support means, said' iilm suplprt means and said system being so positioned ',e ati'. e to each otherand to said screen that the fluorescent image on said screen isreproduced on a film in an area Which is positioned against said supportmeans, said film support means having a cylindrical surface and saidfluorescent screen having an image surface cylindrical about an axis ofrevolution perpendicular to the axis of revolution of the lm supportingsurface.

2. Means for taking X-ray pictures comprising a fluorescent screen, anaspherical lens and spherical mirror system, film support means, saidfilm support means and said lens-mirror system being so positionedrelative to each other and to said screen that the fluorescent image onsaid focal plane of said system, means for feeding a screen isreproduced on a film positioned against said support means, said nlmsupport means hav- .ing a plane surface against Which the imagereceiving portion of the lm rests and said .fiucrescentr screen being`formed as a portion of a sphere convex toward said lens-mirror system.

3. Means for taking X-ray pictures comprising a fluorescent screen, anaspherical lens and spherical mirror system, a. film support forlreceiving and supporting the film, said film support having a film.engaging surface which is flat in one direction of cross section, andsaid fluorescent screen in thesamevdir'ection of cross section being ofcurvilineal shape such thatthe lens-mirror system vfocuses lthefluorescent image upon said film engagingsurface of the support, saidflucrescentA 'screen being convextoward said lensmirror system. s

4. Means for .taking X-ray pictures comprising afluorescent screen, anaspherical lens and-spherical mirror systema`i^ilm -support,.said filmsupport ands'aid Vlens-mirror-system being so positioned relative to,each other and to said screen thatk the fluorescent image on saidscreen is reproduced as a film image at thesurface of said support,saidl supporthaving a film engaging surface-Whichf is flat inonedirection of cross section, and saidfluorescent screen being ofconcave-convex configuration with its convex surface facing thelens-mirror system.l

5. Means-for taking a series of X-ray pictures upona filmstrip, saidmeans comprising a fluorescent screen,- an aspherical lens and sphericalmirror system, a film support positioned at the focal plane of saidsystem, means for feeding a film strip in successive increments acrossvsaid support, said filmv support having `a part cylindrical filmengaging-surface and said fluorescent screen being part cylindrical Withits axis of revolution perpendicular -to the axis ofrevolutionoftheiilmengagingsurface of the support to give a photographicimage sharpvon both of said axes.

6. Means for taking a series of X-ray pictures upon-a filmstrip,-saidgmeans comprising -a iluorescent screen, an aspherical lens andspherical mirror system, a iilmsupport positioned at the lm strip inrsuccessive increments across said support, said film support having aplane nlm engaging surface and said fluorescent screen being formedas-.apfortion of a substantially true sphere Whose center lies on aprolongation of the ing'said screen to said housing, a spherical mirrorin said housing, an aplanatic lens mounted on said housing between saidmirror and said uorescent screen, a film box in said housing inter-gvposed between the lens and the mirror and hav'- ing an open side facingthe mirror, means in said film box for yfeeding lm past the open side ofsaid box facing the mirror, an X-ray opaque member mounted on said boxat the opposite side thereof to exclude direct X-rays from the film.

8. Means for taking X-ray pictures comprising a fluorescent screenhaving a concave side against which an object to be X-rayed ispositioned, an aspherical lens and spherical mirror system, film supportmeans, said lm support means and said lens mirror system being sopositioned relative to each other and to said screen that thefluorescent image of the object positioned on the concave side of thescreen is reproduced on the surface of the lm support means, said filmsupport means including a supporting surface flat in one direction ofcross section for holding the i'llm fiat in said direction within thearea Within which an image is produced by said lens mirror system on thesurface of said support means.

= LEROY M. E. CLAUSING.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS

